Filters may be used to remove particles from air streams. For example, it may be desirable to remove particles from intake air streams to, e.g., gas turbine inlets, emergency power generators, gas compressors, HVAC systems, gas mining operations, etc. A partition may be provided separating a filtration unit into a dirty side and a clean side. The partition has openings in which filters are mounted. Over time, the filter media of a filter becomes spent, e.g., loaded with filtered particles, and the filter is replaced.